The present invention relates to exhaust systems and, in particular, to mufflers for quieting the exhaust noise of a vehicle engine. More particularly, this invention relates to mufflers having stamped outer shells and stamped inner plates.
It is known to construct mufflers using stamp-formed outer shells and inner plates. See, for example, U.S. Pat. No. 5,252,788 to Ernrick et al.; U.S. Pat. No. 5,229,557 to Allman et al.; U.S. Pat. No. 5,147,987 to Richardson et al.; U.S. Pat. No. 5,004,069 to Van Blaircum et al.; U.S. Pat. No. 4,941,545 to Wilcox et al.; U.S. Pat. No. 4,860,853 to Moring; U.S. Pat. No. 4,736,817 to Harwood; and Re. U.S. Pat. No. 33,370 to Harwood.
Stamp-formed mufflers include a plurality of subchambers and tubes formed between the stamped outer shells and inner plates. The subchambers and tubes direct exhaust gas of the vehicle engine through the muffler in a desired manner to quiet the exhaust noise produced by the vehicle engine.
According to the present invention, a muffler is provided including an outer shell defining a chamber and first and second inner plates positioned to lie in the chamber. The second inner plate includes a base portion, a baffle integral with the base portion, and a tube portion integral with the base portion. The base portion includes an outer periphery defining a base portion boundary. The baffle extends between the base portion and the outer shell and the tube portion is positioned outside the boundary of the base portion.
In a preferred embodiment, the second inner plate includes first and second folds that partition the second inner plate into the base portion and first and second baffle segments. The first and second baffle segments cooperate to define the baffle.
In another preferred embodiment, the first inner plate includes a base portion that cooperates with the base portion of the second inner plate to define a first baffle. The baffle of the second inner plate provides a second baffle and the second inner plate includes a third baffle integrally coupled to the base portion of the second inner plate. The base portion of the second inner plate defines a plane that partitions the outer shell into first and second outer shell portions. The second baffle extends between the base portion of the second inner plate and the first outer shell portion and the third baffle extends between the base portion of the second inner plate and the second outer shell portion.
According to a method of the present invention, a method is provided for assembling a muffler including an outer shell, a first inner plate, and a second inner plate. The second inner plate includes a base portion, a first baffle segment integral with the base portion, a second baffle segment integral with the base portion, and a tube portion integral with the base portion. The first baffle segment is positioned in an upright position relative the base portion. The second baffle segment is positioned relative the base portion so that the second baffle is positioned over the tube portion and the first and second baffle segments cooperate to define a baffle. The first inner plate is positioned adjacent the second inner plate and the first and second inner plates are positioned in the outer shell.
Additional features of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.